Ions are used in a plurality of semiconductor processes, such as implantation, amorphization, deposition and etching processes. These ions may be created within an ion source chamber and extracted through an extraction aperture in the ion source chamber.
There are several different types of ion implantation systems. One type is referred to as a beam-line system. In a beam-line system, ions are extracted from an ion source, pass through a mass analyzer to select particular ions based on their mass, energy and charge, and are made into a parallel ribbon ion beam. Beam-line systems may also include deceleration stages, and other components to make the resulting ribbon ion beam more uniform.
The mass analyzer described above is typically a large curved magnet. This magnet bends a beam of ions that all have the same energy in a curve, whose radius is dependent on the ion mass. Ions have a desired mass exit through a resolving aperture, while ions having different masses travel along a curve that does not permit them to exit through the resolving aperture. These magnets are large, expensive and heavy and represent a significant fraction of the total cost of the beam-line system. These magnets also have special safety concerns because the stray magnetic fields can interfere with the operation of pacemakers. Further, these magnets also are a source of environmental concerns, since these magnets consume a large fraction of the electrical power needed to operate the beam-line system.
It would be beneficial if there were apparatus that retains the function of the mass analyzer, but is capable of performing this function at lower cost, space and power. Further, it would be advantageous if this apparatus were easily tunable to select one of a plurality of ions, depending on the process being performed.